Caveat: it works for GNU make only, and it's *really ugly*. So ugly that I
don't
feel like applying it to automake proper.

A GNU make dependency would be a real problem. A dependency on a
properly-working standard make would not be such a problem.

"Again" is not the correct word here -- automake, either patched or not,
has *never* been able to run arbitrarily large test suites. Still, recent
changes might have unintentionally reduced the maximal "testsuite size"
automake is able to handle, and we'd want to fix that. How "big" is the
testsuite you are referring to concretely?

I have not run into any problems when using Ralf's patch, but it
apparently does not address all issues so Ralf backed it out.

My test suite is pretty slim at the moment. About 610 tests (used to
be about 1200) which expand to a list of tests of at least 17903 bytes
when builddir == srcdir, or 36813 bytes with one of my typical build
configurations with builddir != srcdir.